Apparatus and method for controlling speed of a fan via a first control module connected by a cable and/or conductors between a motor and a second control module

ABSTRACT

A fan system includes a motor control module external to a motor housing of a fan assembly. The motor control module includes a speed control module. The fan assembly includes a fan and the motor housing. One or more first conductors are configured to connect the motor control module to a motor in the motor housing. One or more second conductors are configured to connect the motor control module to a host device control module. The host device control module is separate from the motor control module and is configured to generate a control signal. The speed control module is configured to control speed of the fan based on the control signal.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/469,196 filed on May 20, 2009, now U.S. Pat. No. 8,277,196,which claims the benefit of U.S. Provisional Application No. 61/114,168,filed on Nov. 13, 2008. This application claims the benefit of U.S.Provisional Application No. 61/385,928, filed on Sep. 23, 2010. Thedisclosures of the above applications are incorporated herein byreference in their entirety.

FIELD

The present disclosure relates to thermal control systems, and moreparticularly to motor control systems of fans for cooling electroniccircuits.

BACKGROUND

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent the work is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

Cooling fan assemblies may provide airflow to dissipate heat generatedby electronic components. Cooling fan assemblies may include a motorthat drives fan blades. Traditional cooling fan assemblies include aprinted circuit board (PCB) mounted inside a housing of the motor. Fancontrol modules and Hall-effect sensors are mounted on the PCB and usedto control a speed of the motor.

Referring now to FIG. 1, a cooling fan system 100 is shown and includesa PCB 101 that is mounted in a motor housing 102. A motor control module104 is mounted on the PCB 101. Wires 105 connect the PCB 101 to a hostdevice (not shown) via terminals 106 on the PCB 101. An example of ahost device is a personal computer.

The motor housing 102 includes a motor 107. The motor 107 may include atwo-phase brushless direct current (DC) motor. The motor 107 may includefour stator poles: pole A1 108, pole A2 109, pole B1 110, and pole B2112. Each of the stator poles A1 108, A2 109, B1 110, B2 112 may bewound with stator coils 114. The pole A1 108 and the pole A2 109 maycollectively be called “pole pair A”. The pole B1 110 and the pole B2112 may collectively be called “pole pair B”.

The motor control module 104 may apply a voltage and/or current to thestator coils 114 of the pole pair A to generate a magnetic field betweenthe pole A1 108 and the pole A2 109. Applying the voltage and/or currentto the stator coils 114 of the pole pair A may be called “driving phaseA”. The motor control module 104 may provide the voltage and/or currentto the stator coils 114 of the pole pair B to generate a magnetic fieldbetween the pole B1 110 and the pole B2 112. Applying the voltage and/orcurrent to the stator coils 114 of the pole pair B may be called“driving phase B”.

The motor 107 also includes a rotor 116. The rotor 116 may include atleast one permanent magnet. The motor control module 104 may drive phaseA and/or phase B to actuate the rotor 116 about an axle 118. The axle118 may mechanically couple the rotor 116 to the motor housing 102. Themotor housing 102 includes externally attached fan blades 119. The fanblades 119 are collectively referred to as a fan 120. While the rotor116 in FIG. 1 rotates between the stator poles A1 108, A2 109, B1 110,B2 112 the motor 107 may alternatively include a rotor that surroundsthe stator poles A1 108, A2 109, B1 110, B2 112.

The motor control module 104 may alternate between driving phase A anddriving phase B to actuate the rotor 116. At least one Hall-effectsensor 122 may be mounted on the PCB 101 and be used to determine aposition and/or a speed of the rotor 116. For example, the Hall-effectsensor 122 may generate a pulse when a magnetic pole of the rotor 116passes the Hall-effect sensor 122. The motor control module 104 maydetermine whether the rotor 116 is rotating and/or a speed of the rotor116 based on the pulses generated by the Hall-effect sensor 122.

SUMMARY

A fan system is provided and includes a motor control module external toa motor housing of a fan assembly. The motor control module includes aspeed control module. The fan assembly includes a fan and the motorhousing. One or more first conductors are configured to connect themotor control module to a motor in the motor housing. One or more secondconductors are configured to connect the motor control module to a hostdevice control module. The host device control module is separate fromthe motor control module and is configured to generate a control signal.The speed control module is configured to control speed of the fan basedon the control signal.

In other features, the motor control module is connected between atleast one of the first conductors and at least one of the secondconductors. In other features, the fan system further includes a cableconnected to the motor and to the host device control module. The cableincludes the motor control module.

In other features, the motor control module is mounted on a supportmember of the motor housing. The support member includes an opening forpassing air through the support member to contact the temperaturesensor.

In other features, the temperature sensor is mounted on the fan assemblyand in a path of air flowing through the fan assembly. In otherfeatures, the temperature sensor is separate from the motor controlmodule and is mounted on the fan assembly.

In other features, the fan system further includes a connector connectedbetween the one or more first conductors and the one or more secondconductors and external to the fan assembly. The motor control module ismounted on or in the connector. In other features, the motor controlmodule is physically accessible without physically accessing the motorhousing.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description, the claims and the drawings. Thedetailed description and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of thedisclosure.

BRIEF DESCRIPTION OF DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a fan system according to the prior art;

FIG. 2A is a fan system incorporating a connector with a motor controlmodule in accordance with the present disclosure;

FIG. 2B is another fan system incorporating a motor control modulelocated at a host and in accordance with the present disclosure;

FIG. 2C is still another fan system incorporating a rotor that surroundsa stator in accordance with the present disclosure;

FIG. 2D is another fan system illustrating a fan case and relative sizesof fan assembly components in accordance with the present disclosure;

FIG. 2E is yet another fan system incorporating a motor stability modulein accordance with the present disclosure;

FIG. 3 is a fan system illustrating a more detailed view of a motorcontrol module in accordance with the present disclosure;

FIG. 4 illustrates a method of operating a fan system in accordance withthe present disclosure;

FIG. 5 is another fan system incorporating a motor control module in acable and in accordance with the present disclosure; and

FIG. 6 is another fan system incorporating a motor control module in asupport member of a fan assembly and in accordance with the presentdisclosure.

DESCRIPTION

The foregoing description is merely illustrative in nature and is in noway intended to limit the disclosure, its application, or uses. Thebroad teachings of the disclosure can be implemented in a variety offorms. Therefore, while this disclosure includes particular examples,the true scope of the disclosure should not be so limited since othermodifications will become apparent upon a study of the drawings, thespecification, and the following claims. For purposes of clarity, thesame reference numbers will be used in the drawings to identify similarelements. As used herein, the phrase at least one of A, B, and C shouldbe construed to mean a logical (A or B or C), using a non-exclusivelogical OR. It should be understood that steps within a method may beexecuted in different order without altering the principles of thepresent disclosure.

As used herein, the term module may refer to, be part of, or include anApplication Specific Integrated Circuit (ASIC); an electronic circuit; acombinational logic circuit; a field programmable gate array (FPGA); aprocessor (shared, dedicated, or group) that executes code; othersuitable components that provide the described functionality; or acombination of some or all of the above, such as in a system-on-chip.The term module may include memory (shared, dedicated, or group) thatstores code executed by the processor.

The term code, as used above, may include software, firmware, and/ormicrocode, and may refer to programs, routines, functions, classes,and/or objects. The term shared, as used above, means that some or allcode from multiple modules may be executed using a single (shared)processor. In addition, some or all code from multiple modules may bestored by a single (shared) memory. The term group, as used above, meansthat some or all code from a single module may be executed using a groupof processors. In addition, some or all code from a single module may bestored using a group of memories.

The apparatuses and methods described herein may be implemented by oneor more computer programs executed by one or more processors. Thecomputer programs include processor-executable instructions that arestored on a non-transitory tangible computer readable medium. Thecomputer programs may also include stored data. Non-limiting examples ofthe non-transitory tangible computer readable medium are nonvolatilememory, magnetic storage, and optical storage.

Traditional fan assemblies include a printed circuit board (PCB) mountedinside a motor housing. Fan electronics, such as fan control modules andHall-effect sensors, were mounted on the PCB to control the motor. Thus,the motor housing was physically accessed and/or disassembled in orderto alter fan electronics on the PCB. Further, size of the fan assemblywas dependent on the size of the PCB, as the fan assembly needed to belarge enough to enclose the PCB.

Implementations disclosed herein include motor control modules that areexternal to respective motor housings. The motor housings may includevarious types of fan motors. Some types of fan motors are brushedmotors, brushless motors, direct current (DC) motors, alternatingcurrent (AC) motors, etc. The fan motors may have any number of phases.Some fan motors with different numbers of phases are a single-phasemotor, a two-phase motor and a three phase motor.

The motor control modules disclosed herein may be physically accessed,altered and/or replaced without physically accessing and/or opening themotor housings. The motor control modules may not include a Hall-effectsensor. As a result, the motor control modules and corresponding printedcircuit boards (PCBs) may be removed entirely from respective fanassemblies. In addition, sizes of the PCBs are minimized due to thenumber and size of the components incorporated on the PCBs.

In FIG. 2A, a host 199 is shown. The host 199 includes a fan system 200with a fan assembly 201 and a control circuit 202. The fan assembly 201includes a motor 203 in a motor housing 204. The motor 203 may be amotor of one of the types described above or may be, for example, atwo-phase brushless DC motor, as shown. The control circuit 202 includesa motor control module 205 that is external to and/or remote from themotor housing 204 and controls the motor 203.

The motor control module 205 is mounted on or within a connector 206and/or a connector housing 208. The connector 206 is used to connect themotor 203 to a host device control module 209. At least a portion of theconnector 206 may be encased within the connector housing 208. At leasta portion of the motor control module 205 may be encased within theconnector 206 and/or the connector housing 208. The connector housing208 may be a two-part connector with mating components, such as a plugand a receptacle (or socket). Two-part connectors are shown in FIGS. 5and 6. The motor control module may be connected to, mounted on and/orlocated in one or more of the mating components of the connector 206.

The connector 206 may interface with a host device control module 209 ofthe host 199 via conductors 210. The term “conductors” as used hereinmay refer to insulated or non-insulated wires, conductive traces,conductive lines, etc. The host device control module 209 may be, forexample, a control module of an electrical and/or electronic system. Forexample the host may be a personal computer, a server, a projector, arefrigerator, a printer, an electronic instrument, etc. The host devicecontrol module 209 may be a central processing unit (CPU). The fanassembly 201 may be mounted on and/or be proximate to the host devicecontrol module 209 to provide direct cooling to the host device controlmodule 209.

The motor control module 205 may include a PCB, an IC, resistors,capacitors, and/or other electronic components and terminals. The PCBmay be a single-sided or dual-sided PCB. A single-sided PCB haselectronic components only on one side of the PCB. A dual-sided PCB haselectronic components on two sides of the PCB. Incorporating componentson two sides of a PCB allows for the two-sided PCB to be sized smallerthan a single-sided PCB. However, a two-sided PCB is more difficult tomanufacture and has higher associated costs than a single-sided PCB.

In the implementation shown the motor control module 205 includes atemperature sensor (e.g., a thermistor) 211. The temperature sensor 211may be used to detect temperatures of the host 199 (e.g., temperatureswithin the host 199), temperatures of air passing through the fanassembly 201, and/or temperatures of the motor 203. The temperaturesensor 211 and/or the connector 206 may be mounted in a path of the airflowing through the fan assembly 201. The temperature sensor 211 may bemounted on the motor control module 205, on or in the connector 206, onor in the connector housing 208, or elsewhere. Other examples ofmounting locations for the temperature sensor 211 are shown in FIGS. 2E,5 and 6. To further simplify and reduce the size of the motor controlmodule 205, the motor control module 205 may not include the temperaturesensor 211, as further described with respect to FIG. 2E.

The fan assembly 201 includes the motor housing 204. Fan blades 212 areattached to or integrally formed as part of the motor housing 204. Thefan blades 212 and the motor housing 204 may be collectively referred toas a fan 214. The fan 214 may direct air to cool electronic componentsof the host 199, such as the motor control module 205 and/or the hostdevice control module 209. The motor housing 204 includes the motor 203,which includes a stator 215 and a rotor 226.

The stator 215 includes four stator poles: pole A1 216-1, pole A2 216-2,pole B1 216-3, and pole B2 216-4 (collectively stator poles 216). Eachof the stator poles 216 may be wound with stator coils 224-1, 224-2,224-3, 224-4 (collectively stator coils 224), respectively. The motorcontrol module 205 may communicate with the stator poles 216 viaconductors 225 that communicate with terminals 227 on the stator poles216.

The rotor 226 may include at least one permanent magnet (not shown) androtates relative to the stator 215 based on control signal(s) generatedby the motor control module 205 and/or by the host device control module209. The rotor 226 may be mounted on an axle (or rotor shaft 228) thatconnects the rotor 226 to the motor housing 204. In operation, rotationof the rotor 226 rotates the rotor shaft 228 and the motor housing 204relative to the stator 215.

The conductors 210 may include, for example, a ground (or voltagereference) wire 210-1, a voltage source wire 210-2, a speed control wire210-3 and a feedback wire 210-4 (referred to as a “TACHO” wire, whereTACHO is an abbreviation of the term “tachometer”). The speed controlwire 210-3 may receive a pulse width modulation (PWM) signal from thehost device control module 209, which indicates a commanded referencespeed. The feedback wire 210-4 provides a feedback signal generated bythe motor control module 205 to the host device control module 209. Thefeedback signal indicates a current speed of the motor 203. The feedbacksignal may be generated based on a signal from a Hall effect sensorand/or a speed signal from a speed control module. An example of a Halleffect sensor is shown in FIG. 2E. An example of a speed control moduleis shown in FIG. 3.

Although three conductors are shown in FIG. 2A between the connector 206and the motor 203, the fan system 200 may incorporate two or moreconductors between the connector 206 and the motor 203. In theimplementation of FIG. 2A, the motor 203 is a two-phase motor, where theconductors 225 include a ground (or reference) wire 225-1, a first phasewire 225-2 and a second phase wire 225-3. Two of the terminals 227 maybe shorted together and connected to the ground wire 225-1. The othertwo terminals are connected to a respective one of the first phase wire225-2 and the second phase wire 225-3. Alternative implementationsinclude numerous different wire and terminal arrangements, such as afour wire arrangement, where each of the conductors is connected to arespective one of the terminals 227. The four wire arrangement is usedon a three-phase motor, as shown in FIGS. 5 and 6.

The conductors 210 and 225 and other conductors disclosed herein whichare connected to a motor control module may be extended through PCBs ofthe motor control modules and soldered to the PCBs. As an alternative,the conductors may be surface mounted and/or soldered. Surface mountingthe conductors may aid in reducing size of the motor control modules.Wire restraints (not shown) may be used to protect wire connections onthe motor control module depending upon how the conductors are connectedto the motor control modules and/or the application of use.

In FIG. 2B, a fan system 200 ^(I) is shown. The fan system 200 ^(I)includes the fan assembly 201 and a control circuit 202 ^(I). The fanassembly 201 includes the motor housing 204 with the motor 203 and thefan 214. The control circuit 202 ^(I) includes a thermal control module230. The thermal control module 230 is connected to the fan assembly 201via a connector 206 ^(I). The thermal control module 230 is external toand remotely located from the fan assembly 201. The thermal controlmodule 230 includes the host device control module 209 and the motorcontrol module 205 ^(I). In this implementation, the motor controlmodule 205 ^(I) is externally and remotely located from the fan assembly201 and the connector 206 ^(I). As an example, the connector 206 ^(I)may be mounted on a PCB of a host (e.g., the host 199 of FIG. 1) and thefan assembly 201 may be mounted on a housing or case of the host.

The thermal control module 230 may include a PCB and/or one or moresystem-in-packages (SIPs), and/or system-on-a-chips (SOCs). The thermalcontrol module 230 may be a SIP or a SOC. The host device control module209 and the motor control module 205 ^(I) may each be an SOC or beincorporated in a single SIP or a single SOC. In one implementation, thethermal control module 230 includes a PCB and the control modules areSOCs mounted on the PCB. The PCB may be a motherboard when the host is,for example, a personal computer.

The connector 206 ^(I) may include a temperature sensor (or thermistor)211. A temperature signal may be transmitted from the connector 206 ^(I)to the motor control module 205 ^(I) for regulating speed of the fan214. The temperature sensor 211 may alternatively be located on the fanassembly 201.

A first interface 232 may connect the connector 206 ^(I) to the motorcontrol module 205 ^(I) and/or thermal control module 230. The firstinterface 232 may include a cable and/or conductors. In oneimplementation, four conductors 234 are connected between the motorcontrol module 205 ^(I) and the connector 206 ^(I). The four conductors234 may include a ground (or reference wire) 234-1, a temperature signalwire 234-2, and two or more power conductors 234-3, 234-4 for respectivephases of the motor 203.

A second interface 236 may be connected between the motor control module205 ^(I) and the host device control module 209. The interface 236 mayinclude a cable and/or conductors. In one implementation, four or moreconductive traces 238 are connected between the motor control module 205^(I) and the host device control module 209. The conductive traces 238may include a ground (or reference) trace 238-1, a power trace 238-2, aspeed control (e.g., PWM) trace 238-3, and a feedback (e.g., TACHO)trace 238-4. The speed control and feedback traces 238-3, 238-4 may beused to transfer PWM and TACHO signals similar to the speed control andfeedback conductors 210-3, 310-4 of FIG. 2A.

In FIG. 2C, a fan system 200 ^(II) is shown. The fan system 200 ^(II)includes a fan assembly 201 ^(I) and the control circuit 202. The fanassembly 201 ^(I) includes a motor housing 204 ^(I) with a motor 203^(I). The motor 203 ^(I) includes a stator 215 ^(I) and a rotor 240. Thestator 215 ^(I) includes the stator poles 216. The rotor 240 surroundsthe stator poles 216. The rotor 240 rotates around the stator poles 216in response to voltage/current supplied to the stator poles 216.

The rotor 240 may include a rotor shaft 228 ^(I) that is disposed in abearing 242. The bearing 242 may be a sleeve bearing or ball bearingring. The rotor 240 rotates relative to the stator 215 ^(I) via thebearing 242.

The control circuit 202 includes the motor control module 205 and thehost device control module 209. The motor control module 205 is locatedin the connector 206, which may in turn be located in the connectorhousing 208. The connector 206 and/or motor control module 205 areconnected to the host device control module 209 via the conductors 210.The motor control module 205 and/or the connector 206 are connected tothe motor 203 ^(I) via the conductors 225.

Referring now to FIG. 2D, a fan system 200 ^(III) is shown. The fansystem 200 ^(III) includes a fan assembly 201 ^(II) and the controlcircuit 202 ^(II). The fan assembly 201 ^(II) includes a fan case 233.The fan case 233 includes a peripheral wall 250 and a motor housing 204^(II). The motor housing 204 ^(II) is supported in a center of theperipheral wall 250 by support members 252. The fan case 233 may besized for an application of use. Some examples of height and widthdimensions of fan cases are 60 mm×60 mm, 80 mm×80 mm, 92 mm×92 mm and120 mm×120 mm, although the fan case 233 may have different dimensionsdepending on the application of use.

A motor 203 ^(II) is located in the motor housing 204 ^(II). The motor203 ^(II) may be similar to the motor 203 and/or 203 ^(I) of FIGS.2A-2C. The motor 203 ^(II) may include the stator 215 ^(II) with statorpoles 216 ^(I) (or 216 ^(I)-1, 216 ^(I)-2, 216 ^(I)-3, 216 ^(I)-4) andstator coils 224 ^(I) (or 224 ^(I)-1, 224 ^(I)-2, 224 ^(I)-3, 224^(I)-4). The motor 203 ^(II) may include a rotor similar to the rotors226 and 240 of FIGS. 2A-2C and rotate in or around the stator 215 ^(II).Fan blades 212 ^(I) are attached or integrally formed as part of themotor housing 204 ^(II) and together are collectively referred to as afan 214 ^(I).

The control circuit 202 ^(II) includes a motor control module 205 ^(II),the connector 206 with the housing 208, and a host device control module209 ^(I). The motor control module 205 ^(II) may be mounted on or in theconnector 206 and is configured to control speed of the fan 214 ^(I).The motor control module 205 ^(II) may include the temperature sensor211 and adjust speed of the fan 214 ^(I) based on a temperature signalfrom the temperature sensor 211. The temperature sensor 211 may bemounted on the motor control module 205 ^(II), on or in the connector206 and/or on or in the connector housing 208. The host device controlmodule 209 ^(I) is connected to the motor control module 205 ^(II) viathe conductors 210. The motor control module 205 ^(II) is connected tothe motor 203 ^(II) via the conductors 225. The conductors 225 may berouted in a channel of one of the support members 252, as shown in FIGS.5 and 6.

In the implementation of FIG. 2D, the motor control module 205 ^(II) isnot located in the motor housing 204 ^(II). Also, a Hall effect sensoris not incorporated in the fan assembly 201 ^(II) and/or in the motorhousing 204 ^(II). This allows for a smaller motor housing 204 ^(II) tobe used due to a reduction in the number of components incorporated inthe motor housing 204 ^(II). A smaller sized motor housing, allows forlarger fan blades to be used. If a size of the fan case 233 for the fanassembly 201 ^(II) is unchanged, the smaller the motor housing 204^(II), the more space between the fan case 233 and the motor housing 204^(II) for the fan blades 212 ^(I).

Although the control modules 205 ^(II) and 209 ^(I) may be similar tothe control modules 205, 205 ^(I) and 209 of FIGS. 2A-2D, the controlmodules 205 ^(II) and 209 ^(I) are configured to accommodate the motor203 ^(II) and the fan blades 212 ^(I). The motor 203 ^(II) may provide ahigher output torque than the motors 203 and 203 ^(I) of FIGS. 2A-2C.The motor 203 ^(II) may provide a higher output torque to accommodatefor the size of the fan blades 212 ^(I), which may be larger than thefan blades 212 of FIGS. 2A-2C. The increased size of the fan blades 212^(I) provides an increased amount of air flow for improved coolingefficiency. For this reason, a motor with a higher output torque may beused.

Traditionally, the ability to reduce the size of a motor housing waslimited due to the incorporation of a PCB including a Hall effect sensorin the motor housing. Since a PCB and/or a Hall effect sensor may not beincorporated in the motor housings disclosed herein, the size of thecorresponding fan assemblies may be the same or smaller than the size ofa traditional fan assembly. The fan assemblies disclosed herein may havemotors, motor housings and/or fan blades that are smaller in size thantraditional motors, motor housings and/or fan blades.

Referring now to FIG. 2E, a fan system 200 ^(IV) is shown. The fansystem 200 ^(IV) includes a fan assembly 201 ^(III) and a controlcircuit 202 ^(III). The fan assembly 201 ^(III) includes the fan 214^(I) with the motor housing 204 ^(II). The motor housing 204 ^(II)encases the motor 203 ^(II). The motor 203 ^(II) includes the statorpoles 216 ^(I) and the stator coils 224 ^(I). The control circuit 202^(III) includes a motor control module 205 ^(III) and the host devicecontrol module 209 ^(I). The motor control module 205 ^(III) may belocated in the connector 206 and/or connector housing 208. The hostdevice control module 209 ^(I) is connected to the motor control module205 ^(III) via the conductors 210. The motor control module 205 ^(III)is connected to the motor 203 ^(II) via the conductors 225.

A stability module 260 may be mounted in or on the motor housing 204^(II) to provide mechanical stability for electrical connections in themotor housing 204 ^(II). The conductors 225 may be connected to thestability module 260, which communicates with terminals 227 rather than,as in FIGS. 2A-2D, directly soldered or otherwise directly connected tothe terminals 227.

The stability module 260 may include a PCB 261. The stability module maynot include any sensors or may, for example include a temperature sensor262 and/or a Hall effect sensor 264. The Hall effect sensor 264 may beused to detect and/or determine position, movement, and/or speed of thefan 214 ^(I). Alternatively, position, movement, and/or speed of the fan214 ^(I) may be determined by a speed control module of the motorcontrol module 205 ^(III). The temperature sensor 262 and the Halleffect sensor 264 may have respective conductors 266, 268 that areconnected to the motor control module. Although the stability module 260as shown includes a temperature sensor 262 and/or a Hall effect sensor264, the stability module 260 may not include the temperature sensorand/or the Hall effect sensor. The temperature sensor 262 may not belocated on the stability module 260. The temperature sensor 262 may belocated on the motor housing 204 ^(II), on the fan case 233 and/or oneof the support members 252 of the fan assembly 201 ^(III), on the motorcontrol module 205 ^(III), on the connector 206, etc. The stabilitymodule 260 may not include control functionality, such as a controlmodule.

Referring now to FIG. 3, a fan system 200 ^(V) incorporating a motorcontrol module 205 ^(IV) is shown. The motor control module 205 ^(IV)may be used in the fan systems of FIGS. 2A-2E, 5 and 6. The motorcontrol module 205 ^(IV) may be located in the connector 206, include aPCB or be an IC, and communicate with the host device control module 209via the conductors 210. The motor control module 205 ^(IV) may include apower control module 272, a speed control module 273, and an inductivesensing system 274. The inductive sensing system 274 may include thespeed control module 273, a back electromotive force (BEMF) detectionmodule 275 and/or a current detection module 276. The power controlmodule 272, BEMF detection module 275, and current detection module 276may communicate with terminals 227 on the fan assembly 201 via aninterface 277. The fan assembly 201 may be replaced with one of theother fan assemblies disclosed herein.

The power control module 272 may apply a voltage and/or current to oneor more of the stator coils 224 of the fan assembly 201. For example,the power control module 272 may alternate between driving stator coils224-1, 224-2 and 224-3, 224-4 to rotate the rotor 226.

While the inductive sensing system 274 is described using a two-phasebrushless DC motor, the inductive sensing system 274 may also beimplemented in other motor systems (e.g., one-phase or three-phase motorsystems).

The BEMF detection module 275 may detect BEMF voltage from undriven onesof the stator coils 224. In a stator coil that is not powered, a BEMFvoltage having a sinusoidal waveform is generated by permanent magnets(not shown) in the rotor 226. Specifically, as the permanent magnets ofthe rotor 226 pass by the unpowered coil (e.g. 224-4), a current isinduced in the unpowered coil 224-4. In one implementation, the powercontrol module 272 initially provides voltage and/or current to statorcoils 224-1, 224-2 but not coil(s) 224-3 and/or 224-4. The BEMFdetection module 275 detects BEMF from the coil 224-3 and/or the coil224-4.

The speed control module 273 determines when the magnets of the rotor226 pass by the coil 224-3 and/or the coil 224-4 based on signals fromthe BEMF detection module 275. The speed control module 273 may includedata indicating distances between and/or positions of the stator poles216.

In an alternative implementation, the current detection module 276detects current at each of the stator coils 224-1, 224-2, 224-3, 224-4.The speed control module 273 determines positions of the stator poles216 based on the detected current and the detected BEMF.

The speed control module 273 may determine the rotational speed of therotor 226 and whether the rotor 226 is moving and/or stuck based on thewaveform of the detected BEMF and the position of the stator poles 216.The speed control module 273 may generate control signals to adaptivelyadjust the rotation speed of the motor 203.

The fan systems disclosed herein may be operated using numerous methods,an example method is provided by the method of FIG. 4. In FIG. 4, amethod of operating a fan system is shown.

Although the following tasks are primarily described with respect to theimplementations of FIGS. 2A-2E, 5 and 6, the tasks may be easilymodified to apply to other implementations of the present disclosure.The tasks may be iteratively performed.

The method may begin at 501. At 502, the power control module 272 drivesa motor (e.g., one of the motors 203-203 ^(II)). In one implementation,the power control module 272 rotates a rotor (e.g., the rotor 226 or therotor 240) by supplying a drive current and/or a drive voltage to thestator coils of a stator (e.g., stator coils 224 of the stator 215). At504, the BEMF detection module 275 detects the BEMF from the statorcoils that are not supplied with the drive current or the drive voltage.At 506, the current detection module 276 senses current at terminals ofthe stator coils (e.g., the terminals 227).

At 508, the speed control module 273 determines the relative positionsof the stator and the rotor based on the detected BEMF and/or thedetected current. The speed control module 273 selects one of the statorcoils according to the detected relative positions of the stator and therotor.

At 510, the power control module 273 supplies the drive current or thedrive voltage to the selected coil to rotate the rotor in apredetermined direction at a desired speed. At 512, the speed controlmodule 273 may determine that the speed of the rotor is different than adesired (or predetermined) speed based on the BEMF and/or the currentdetected from motor. In one implementation, the speed control module 273may determine a difference (i.e., an error) between the desired speedand the measured (or actual) speed. The speed control module 273 mayreceive the desired speed from, for example, the host device controlmodule 209.

The host device control module 209 may command to start or stop the fan214 and/or indicate a reference speed via a control signal (representedby signal line 280). The speed control module 273 may convert thereference speed to the desired speed based on, for example, thetemperature signal from the temperature sensor 211, characteristics 278of the fan assembly 201, etc. The characteristics of the of the fanassembly 201 may be stored in memory 229 of the motor control module 205^(IV) and include size of the fan blades 212, size, type, power output,etc. of the motor 203, and/or other fan assembly characteristics.

At 514, if there is a difference between the actual speed and thedesired speed, the speed control module 273 may determine whether themotor is stuck. If the motor is stuck, task 502 may be performed,otherwise task 516 is performed. At 516, the speed control module 273may provide a signal to the power control module 272 to adjust the powersupplied to the motor. In other words, the speed control module 273 maygenerate a control signal to compensate for the difference. In oneimplementation, the speed control module 273 adaptively outputssuccessive control signals to the power control module 272 in order toadjust the speed of the motor to the desired value.

The above-described tasks are meant to be illustrative examples; thetasks may be performed sequentially, synchronously, simultaneously,continuously, during overlapping time periods or in a different orderdepending upon the application.

In FIG. 5, a fan system 200 ^(VI) incorporating a motor control module205 ^(II) in a cable 288 is shown. The fan system 200 ^(VI) includes afan assembly 201 ^(IV) and a control circuit 202 ^(IV). The fan assembly201 ^(IV) includes a fan case 233 ^(I). The fan case 233 ^(I) includesthree of the support members 252 and a channeled support member 252^(I). The support members 252 and 252 ^(I) support the fan 214 ^(I). Thefan 214 ^(I) includes the motor housing 204 ^(II) and the fan blades 212^(I). The motor housing 204 ^(II) encases the motor 203 ^(II). The motor203 ^(II) includes the stator 215 and a rotor (e.g., the rotor 226 orthe rotor 240).

The channeled support member 252 ^(I) may be ‘U’-shaped, open and/orinclude a channel 290 for conductors 225 ^(I) to extend from the motorhousing 204 ^(II) to the peripheral wall 250 of the fan case 233. Theconductors 225 ^(I) may be connected to a first connector 292 externalto the fan case 233 ^(I).

The control circuit 202 ^(IV) includes a motor control module assembly300 and the host device control module 209. The motor control moduleassembly 300 may include a motor control module 205 ^(II), a secondconnector 302 and/or a third connector 304. The motor control module 205^(II) may be connected to the second and third connectors 302 and 304via respective sets of conductors 306, 308 (may be referred to as thirdand fourth sets of conductors). The second connector 302 connects to thefirst connector 292. The third connector 304 connects to a fourthconnector 310. The fourth connector 310 is connected to the host devicecontrol module via conductors 210 ^(I). The motor control moduleassembly 300 may be connected in series or in parallel with theconductors 210 ^(I) and the conductors 225 ^(I) to form the cable 288.The cable 288 extends between the motor housing 204 ^(II) and the hostdevice control module 209.

The motor control module 205 ^(II) may be integrated into the cable 288without use of connectors. For example, the motor control module 205^(II) may be integrated into the cable 288 without use of the connectors292, 302, 304, 310. Wires and/or conductors, such as the conductors 210,of the cable 288 may be connected, for example, directly to the motorcontrol module 205 ^(II).

Width W of the motor control module 205 ^(II) may be less than or equalto 4 times a diameter D of each of the conductors 225 ^(I) (or W≦4D or Wis less than or equal to an overall width of the conductors 225 ^(I)).The motor control module 205 ^(II), the first set of conductors 306 andthe second set of conductors 308 may be shrink wrapped to protect themotor control module 205 ^(II) and wire connections therewith.

As shown, the motor control module 205 ^(II) is connected alongconductors between the motor housing 204 ^(II) and the host devicecontrol module 209. This allows the motor control module 205 ^(II) to beplaced at various locations and be replaced without opening the motorhousing 204 ^(II) and/or disassembling the fan assembly 200 ^(VII).Incorporation of the connectors 292, 302, 304, 310 allows the motorcontrol module 205 ^(II) to be easily replaced without cutting,splicing, and/or soldering conductors. This provides a modular designand allows for testing of different motor control modules. For example,the motor control module 205 ^(II) may be replaced with a differentmotor control module (e.g., the motor control module 205 or other motorcontrol module).

In FIG. 6, a fan system 200 ^(VII) incorporating a motor control module205 ^(II) in the support member 252 ^(I) is shown. The fan system 200^(II) includes a fan assembly 201 ^(V) and a control circuit 202 ^(V).The fan assembly 201 ^(V) includes the fan case 233 ^(I). The fan case233 ^(I) includes three of the support members 252 and a channeledsupport member 252 ^(I). The support members 252 and 252 ^(I) supportthe fan 214 ^(I). The fan 214 ^(I) includes the motor housing 204 ^(II)and the fan blades 212 ^(I). The motor housing 204 ^(II) encases themotor 203 ^(II). The motor 203 ^(II) includes the stator 215 and a rotor(e.g., the rotor 226 or the rotor 240).

The channeled support member 252 ^(I) may be ‘U’-shaped and/or include achannel 290 for conductors 225 ^(I) (first set of conductors) to extendfrom the motor housing 204 ^(II) to the motor control module 205 ^(II).Although the motor control module 205 ^(II) is shown as beingincorporated in the support member 252 ^(II), the motor control module205 ^(II) may be incorporated in other members of the fan case 233 ^(I).For example, the motor control module 205 ^(II) may be incorporated inthe peripheral wall 250. The channel 290 may be open on one side toallow access to the motor control module 205 ^(II). Any side of thechannel 290 may be open. Another set of conductors 320 may be connectedto and extend from the motor control module 205 ^(II) to a firstconnector 322 external to the fan case 233 ^(I).

The control circuit 202 ^(V) includes the motor control module 205 ^(II)and the host device control module 209. The motor control module 205^(II) is located in the channel 290 of the support member 252 ^(I). Thefirst connector 322 is connected to a second connector 324, which isconnected to the host device control module 209 via the conductors 210.

Width W1 of the motor control module 205 ^(II) may be less than or equalto 4 times a diameter D of each of the conductors 225 ^(I) (or W≦4D)and/or less than an inner width W2 of the channel 290. The widthdimensions of the motor control module disclosed herein do not refer toa thickness of a PCB and/or IC. The width dimensions may refer to, forexample, front or top view surface dimensions. The motor control module205 ^(II) and the conductors 225 ^(I), 320 may be shrink wrapped toprotect the motor control module 205 ^(II) and corresponding wireconnections.

When the motor control module 205 ^(II) includes a temperature sensor211, the temperature sensor may protrude from the motor control module205 ^(II) and be in contact with air passing through the fan case 233^(I). The temperature sensor 211 may protrude from the shrink wrapand/or extend from the channel 290. The support member 252 ^(I) mayinclude one or more openings 326 (one is shown) to allow air to passthrough the support member 252 ^(I) and come in contact with thetemperature sensor 211.

The motor control module 205 ^(II) may be connected in series with theconductors 225 ^(I), the conductors 320, the connectors 322, 324 and theconductors 210 ^(I) to form a cable 288 ^(I). The cable 288 ^(I) extendsbetween the motor housing 204 ^(II) and the host device control module209.

As shown, the motor control module 205 ^(II) is connected alongconductors between the motor housing 204 ^(II) and the host devicecontrol module 209 and in the center of the channel 290 between themotor housing 204 ^(II) and the peripheral wall 250 of the fan case 233^(I). This allows the motor control module 205 ^(II) to be protected bythe support member 252 ^(I) and for the temperature sensor 211 to beplaced in the middle of the air flow path that passes through the fanassembly 200 ^(VII). The motor control module 205 ^(II) may be placedanywhere along support member 252 ^(I). Connectors may be incorporatedbetween the motor control module 205 ^(II) and the motor housing 204^(II) to allow for easy replacement of the motor control module 205^(II) and/or testing of multiple motor control modules without openingthe motor housing 204 ^(II).

Also, the implementations of FIGS. 5 and 6 allow for different fanassemblies and/or motor control modules to be tested. For example, inFIGS. 5 and 6 the fan assemblies 201 ^(V) and 201 ^(VI) may be swappedout with other fan assemblies by disconnecting the connectors 292, 322.

By having the motor control modules disclosed herein be outside ofrespective motor housings, air temperatures outside of the motorhousings and/or corresponding hosts can be more accurately detected. Asthe temperature sensors are not located in the motor housings thetemperature sensors are less susceptible to increased temperatureswithin the motor housings.

Also, by not incorporating a Hall effect sensor and/or a temperaturesensor on a PCB, SIP and/or SOC of a motor control module, moreflexibility is provided in design of a fan motor, motor housing, and fancase. Separation of a Hall effect sensor and/or a temperature sensorfrom a motor control module and/or the elimination of the Hall effectsensor minimizes the number of components in the motor control module.This allows for the motor control module to be incorporated in a cable,in a support member or other member of a fan assembly, and/or elsewherein a host and external to a fan assembly. Removal of the temperaturesensor from the motor housing can also reduce noise in the temperaturesignal.

In addition, by separating the motor control module from the motorhousing of a fan assembly, design changes can quickly and easily be madeto the motor control module. For example, the motor control module maybe reprogrammed or replaced without opening and/or entering the motorhousing.

The broad teachings of the disclosure can be implemented in a variety offorms. Therefore, while this disclosure includes particular examples,the true scope of the disclosure should not be so limited since othermodifications will become apparent upon a study of the drawings, thespecification, and the following claims.

What is claimed is:
 1. A fan system comprising: a first control moduleexternal to a motor housing of a fan assembly and comprising a speedmodule, wherein the fan assembly comprises a fan and the motor housing;and a cable comprising a first set of conductors configured to connect amotor in the motor housing to a first connector, a second set ofconductors configured to connect a second connector to the first controlmodule, wherein the second connector is configured to connect to thefirst connector, a third set of conductors configured to connect thefirst control module to a third connector, wherein the second set ofconductors, the second connector, the first control module, the thirdset of conductors, and the third connector are implemented as anassembly, and wherein the assembly is removable from the cable via thesecond connector and the third connector, and fourth set of conductorsconfigured to connect a fourth connector to a second control module,wherein the fourth connector is configured to connect to the thirdconnector, and wherein the second control module is separate from thefirst control module and is configured to generate a control signal,wherein the first control module is configured to detect an inducedvoltage in a first stator coil within the fan housing, via the first setof conductors and the second set of conductors, without receiving asignal from a sensor in the fan housing, the speed module is configuredto (i) control a speed of the fan based on the control signal, (ii)detect a position of the fan based on the induced voltage in the firststator coil, and (iii) adjust the speed of the fan from a first speed toa second speed based on the position, and the first speed and the secondspeed are greater than zero.
 2. The fan system of claim 1, wherein thefirst control module includes one of a printed circuit board, asystem-in-a-package, and a system-on-a-chip.
 3. The fan system of claim1, wherein a width of the first control module is less than or equal toa width of at least one of the second set of conductors and the thirdset of conductors.
 4. The fan system of claim 1, wherein the firstcontrol module includes a temperature sensor.
 5. The fan system of claim4, wherein the temperature sensor is separate from the first controlmodule and is mounted on the fan assembly.
 6. The fan system of claim 4,further comprising a stability module in or mounted on the motorhousing, wherein: the stability module comprises a printed circuitboard; and the temperature sensor is mounted on the printed circuitboard.
 7. The fan system of claim 1, further comprising a temperaturesensor configured to generate a temperature signal, wherein the firstcontrol module is configured to adjust the speed of the fan based on thetemperature signal, and wherein at least one of the first control moduleincludes the temperature sensor or the temperature sensor is mounted onthe fan assembly.
 8. The fan system of claim 1, wherein the firstcontrol module is physically accessible without physically accessing themotor housing.
 9. The fan system of claim 1, further comprising the fanassembly, wherein: the fan assembly is implemented in a host device; thespeed module is configured to control the speed of the fan to control anamount of air current flowing in the host device; the fan generates theair current to cool an electronic circuit in the host device; and thehost device is a computer.
 10. The system of claim 1, wherein: the firstcontrol module is configured to (i) receive a temperature signal from atemperature sensor, wherein the temperature signal indicates atemperature within a host device, (ii) receive a command signal from thesecond control module, wherein the command signal indicates a referencespeed, and (iii) based on the temperature signal and a characteristic ofthe fan assembly, convert the reference speed to a resultant speed; andthe speed module is configured to control the speed of the fan based onthe resultant speed.
 11. The system of claim 10, wherein thecharacteristic of the fan assembly is one of a size of fan blades of thefan, a type of the motor, a size of the motor, and a power output of themotor.
 12. The system of claim 1, wherein: the first control module isconfigured to (i) receive a command signal from the second controlmodule, wherein the command signal indicates a reference speed, and (ii)based on characteristics of the fan assembly, convert the referencespeed to a resultant speed; the characteristics of the fan assemblyinclude a size of fan blades of the fan, a type of the motor, a size ofthe motor, and a power output of the motor; and the speed module isconfigured to control the speed of the fan based on the resultant speed.13. The system of claim 1, wherein the speed module is configured to:compare the control signal to the speed of the fan, wherein the controlsignal indicates the second speed; determine a difference between thespeed of the fan and the second speed; based on the difference betweenthe speed of the fan and the second speed, determine whether the motoris stuck and the fan is not rotating; refrain from adjusting the speedof the fan if the motor is stuck and the fan is not rotating; and adjustthe speed of the fan if (i) the fan is rotating, and (ii) the speed ofthe fan is not equal to the second speed.
 14. A fan system comprising: afirst control module external to a motor housing of a fan assembly,wherein the fan assembly comprises a fan and the motor housing; a firstset of conductors configured to connect the first control module to amotor in the motor housing; and a second set of conductors configured toconnect the first control module to a second control module, wherein thesecond control module is separate from the first control module and isconfigured to generate a control signal, wherein the first controlmodule is configured to detect an induced voltage in a first stator coilwithin the motor housing, via the first set of conductors and the secondset of conductors, without receiving a signal from a sensor in the motorhousing, control a speed of the fan based on the control signal, detecta position of the fan based on the induced voltage in the first statorcoil, and adjust the speed of the fan from a first speed to a secondspeed based on the position, wherein the first speed and the secondspeed are greater than zero.
 15. A fan system comprising: a firstcontrol module external to a motor housing of a fan assembly, whereinthe fan assembly comprises a fan and the motor housing; a first set ofconductors configured to connect the first control module to a motor inthe motor housing; and a second set of conductors configured to connectthe first control module to a second control module, wherein the secondcontrol module is separate from the first control module and isconfigured to generate a control signal, wherein the first controlmodule comprises a power control module configured to supply power to afirst stator coil and not to a second stator coil, wherein the firststator coil and the second stator coil are implemented in the fanhousing, a detection module configured to detect an induced voltage inthe second stator coil via the first set of conductors and the secondset of conductors, and a speed module configured to (i) control a speedof the fan based on the control signal, (ii) detect a position of thefan based on the induced voltage in the second stator coil, and (iii)adjust the speed of the fan from a first speed to a second speed basedon the position, wherein the first speed and the second speed aregreater than zero.
 16. The system of claim 15, wherein the detectionmodule is configured to detect the induced voltage in the second statorcoil without a receiving signal from a sensor in the fan housing.
 17. Amethod of operating a fan system comprising: providing a first controlmodule external to a motor housing of a fan assembly, wherein the firstcontrol module comprises a speed module, and wherein the fan assemblycomprises a fan and the motor housing; providing one or more firstconductors configured to connect the first control module to a motor inthe motor housing; providing one or more second conductors configured toconnect the first control module to a second control module of a hostdevice, wherein the second control module is separate from the firstcontrol module; generating a control signal via the second controlmodule; and via the speed module, controlling a speed of the fan basedon the control signal, comparing the control signal to the speed of thefan, wherein the control signal indicates a predetermined speed, andwherein the predetermined speed is greater than zero, determining adifference between the speed of the fan and the predetermined speed,based on the difference between the speed of the fan and thepredetermined speed, determining whether the motor is stuck and the fanis not rotating, refraining from adjusting the speed of the fan if themotor is stuck and the fan is not rotating, and adjusting the speed ofthe fan if (i) the fan is rotating, and (ii) the speed of the fan is notequal to the predetermined speed.
 18. The method of claim 17, whereinthe first control module comprises a temperature sensor, and wherein themethod further comprises: positioning the temperature sensor in a pathof air flowing through the fan assembly; detecting temperature of theair via the temperature sensor; and adjusting the speed of the fan basedon the temperature.
 19. The method of claim 17, wherein the firstcontrol module is one of: mounted on a support member of the motorhousing; and integrated in a cable extending between the second controlmodule and the fan assembly.
 20. The method of claim 17, furthercomprising: providing a cable between the second control module and thefan assembly; connecting the first control module between the secondcontrol module and the fan assembly along the cable via connectors;testing the first control module subsequent to connecting the firstcontrol module to the cable; and replacing the first control module bydisconnecting the first control module from the cable via the connectorsbased on results generated from the testing of the first control module.